RxPonder clinical trial results indicate that racial disparities continue to be a major health care challenge.
Non-Hispanic Black women with hormone receptor (HR)-positive, human epidermal growth factor receptor-2 (HER2)-negative, lymph node-positive breast cancer had worse outcomes than Asian, Hispanic, and non-Hispanic White patients, despite similar 21-gene recurrence scores (RS), according to the results of a study presented at the San Antonio Breast Cancer Symposium (SABCS) in Texas on December 6, 2022.1
“Racial disparities in breast cancer outcomes continue to be a major health care challenge, with Black women more likely to die from the disease than non-Black women,” Yara Abdou, MD, assistant professor at the University of North Carolina at Chapel Hill and Lineberger Comprehensive Cancer Center, said in a statement.1
“There is now wide-ranging evidence for differences in tumor biology contributing to this disparity," she said. "Understanding these differences will help us discover new opportunities for intervention that will ultimately reduce cancer health disparities.”1
Black women have a 4% lower incidence of breast cancer but a 40% higher breast cancer mortality than White women, Abdou said at a SABCS press conference on December 6, 2022.2
In the study, investigators analyzed clinical outcomes related to ethnicity and race in the RxPONDER clinical trial (NCT01272037), which aimed to assess the value of the 21-gene RS in patients with lymph node-positive, HR-positive/HER2-negative breast cancer and the benefit of adjuvant chemotherapy.1
The 21-gene RS is a genomic test measuring the expression level of a group of genes in the tumor tissue to predict the risk of breast cancer recurrence and response to therapy. Results are measured on a scale of 0 to 100.1
The test is a key tool to guide treatment decisions among women with early-stage breast cancer, Abdou said in the statement.1
The study included 4048 women with HR-positive/HER2-negative breast cancer who had 1 to 3 positive axillary lymph nodes and an RS of 25 or lower, which indicates intermediate or low risk.1
Asian, Hispanic, non-Hispanic Black, and non-Hispanic White patients represented 8%, 15.1%, 6.1% and 70% of the study composition, respectively.1
Investigators found that the 21-gene RSs were similar across all racial subgroups, and there were no significant differences in tumor size and in the number of lymph nodes involved. However, Hispanic and non-Hispanic Black patients had a higher frequency of high-grade tumors at 14.1% and 17.7%, respectively, than did Asian and non-Hispanic White women at 6.5% and 10.2%, respectively.1
The 5-year invasive disease-free survival (IDFS) rate, or the percentage of patients who were alive and free of breast cancer or any other type of invasive cancer, was also lower for non-Hispanic Black patients at 87.2% compared with Asian women at 93.9%, Hispanic patients at 91.4% and non-Hispanic White women at 91.5%.1
After adjusting for age, grade, menopausal status, RS, and treatment arm, non-Hispanic Black patients had a 37% increased risk of invasive cancer compared with non-Hispanic white women. Additionally, non-Hispanic Black patients had lower distant relapse-free survival (DRFS), which is defined as the time from surgery to the first distant recurrence, than did non-Hispanic White women.1
According to the RxPONDER trial results, which were initially presented at SABCS in 2020, premenopausal women with HR-positive/HER2-negative breast cancer with 1 to 3 positive lymph nodes and RS of 25 or lower benefited from the use of chemotherapy, whereas postmenopausal women did not. In this new analysis by race, investigators found that race did not predict the relative benefit of adding chemotherapy to endocrine therapy, as the clinical outcome by treatment arm was not significantly different between non-Hispanic Black and non-Hispanic white patients for DRFS and IDFS.1
1. Black women with breast cancer may have worse outcomes than peers despite similar genetic recurrence scores. American Association for Cancer Research. News release. December 6, 2022. Accessed December 6, 2022. https://www.aacr.org/about-the-aacr/newsroom/news-releases/black-women-with-breast-cancer-may-have-worse-outcomes-than-peers-despite-similar-genetic-recurrence-scores/
2. Press conference I. San Antonio Breast Cancer Symposium. December 6, 2022.